Warren Buffett, the famed US investor who heads Berkshire Hathaway Inc, replaced his friend and Microsoft Corp founder Bill Gates as the richest man in the world, Forbes magazine said on Wednesday.

The magazine estimated Buffett's worth at $62 billion in its annual ranking of the world's wealthiest people.

Mexican telecoms tycoon Carlos Slim came in second with an estimated worth of $60 billion, pushing Gates to third place after 13 years of holding the No. 1 spot.

The magazine estimated Gates' worth at $58 billion.

Buffett's rise to No. 1 was particularly noteworthy, Forbes said, as it came at a time of great financial turmoil and as Buffett has begun to siphon off part of his fortune to charity.

"Even though he is giving away a piece of his fortune each year, the stock of Berkshire Hathaway, the source of Warren Buffet's wealth, has been rising very rapidly," Chief Executive of Forbes Magazines Steve Forbes said, noting Buffett's fortune climbed $10 billion in the last calendar year.

Buffett in June 2006 announced plans to give 85 percent of his fortune away, granting it to the Bill & Melinda Gates Foundation and four family charities. Bill Gates serves on the board of directors of Berkshire Hathaway and is a long-time bridge buddy of Buffett's. Gates has also given a substantial amount of his fortune to the foundation.

Buffett, often called the Sage of Omaha, has been lauded among investors for his preference for investing in larger companies with easy-to-understand businesses, large or dominant market shares, consistent earnings, and strong management.

Gates has held the No. 1 spot since 1995, when he unseated Yoshiaki Tsutsumi, a Japanese real estate tycoon. Tsutsumi fell off the billionaire's list last year after receiving a suspended prison sentence for falsifying financial statements and insider trading in 2005.

China's real estate billionaire Yang Huiyan ranked first among all the 42 Chinese richest people on the list.